Submission #124553

#	Time	Username	Problem	Language	Result	Execution time	Memory
124553		semiauto	Sure Bet (CEOI17_sure)	C++14	100 / 100	231 ms	5232 KiB

sure

#include <bits/stdc++.h>
using namespace std;
int n,i,j,pos;
double s,ans;
double a[100001],b[100001],sum[100001],pre[100001];
int main() {
    cin>>n;
    for (i=1;i<=n;i++)
        cin>>a[i]>>b[i];
    sort(a+1,a+n+1);
    sort(b+1,b+n+1);
    for (i=1;(2*i)<=n;i++) {
        swap(a[i],a[n-i+1]);
        swap(b[i],b[n-i+1]);
    }
    for (i=1;i<=n;i++) {
        sum[i]=sum[i-1]+b[i];
        pre[i]=max(pre[i-1],sum[i]-i);
    }
    for (i=1;i<=n;i++) {
        s+=a[i];
        pos=0;
        for (j=20;j>=0;j--) {
            if (pos+(1<<j)>n)
                continue;
            if (sum[pos+(1<<j)]<=s)
                pos+=(1<<j);
        }
        if (pos>0)
            ans=max(ans,pre[pos]-i);
        if (pos<n)
            ans=max(ans,s-pos-1-i);
    }
    printf("%.4f\n",ans);
}

• Subtask 1: 20 / 20
• Subtask 2: 40 / 40
• Subtask 3: 40 / 40